[libvirt-users] CentOS 6 and 1.3.3

[Brian Rak]

libvirt 1.3.3 seems to have introduced some kind of issue on CentOS 6 
(no systemd).  After upgrading, libvirt would take an incredibly long 
time to get to a state where it would actually respond to a simple 
'virsh list' command.

Looking at verbose output showed this repeating at exactly 30s intervals

2016-04-12 19:40:57.142+0000: 14929: info : 
virEventPollDispatchHandles:507 : EVENT_POLL_DISPATCH_HANDLE: watch=1 
events=1
2016-04-12 19:40:57.142+0000: 14929: info : virEventPollRunOnce:641 : 
EVENT_POLL_RUN: nhandles=116 timeout=-1
2016-04-12 19:40:57.143+0000: 15223: info : virObjectRef:296 : 
OBJECT_REF: obj=0x7fb944181bc0
2016-04-12 19:40:57.144+0000: 15223: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb944181bc0
2016-04-12 19:40:57.157+0000: 15223: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb944253020
2016-04-12 19:40:57.157+0000: 15223: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb944309450
2016-04-12 19:40:57.157+0000: 15223: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb94400ca90
2016-04-12 19:41:27.147+0000: 15224: info : virDBusCall:1577 : 
DBUS_METHOD_REPLY: 'org.freedesktop.DBus.ListActivatableNames' on 
'/org/freedesktop/DBus' at 'org.freedesktop.DBus'
2016-04-12 19:41:27.148+0000: 15224: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb94400ca90
2016-04-12 19:41:27.148+0000: 15224: info : virObjectRef:296 : 
OBJECT_REF: obj=0x7fb94400ca90
2016-04-12 19:41:27.148+0000: 15224: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb94400ca90
2016-04-12 19:41:27.148+0000: 15224: info : virObjectRef:296 : 
OBJECT_REF: obj=0x7fb94400ca90
2016-04-12 19:41:27.151+0000: 15224: info : virObjectUnref:259 : 
OBJECT_UNREF: obj=0x7fb94400ca90
2016-04-12 19:41:27.151+0000: 15224: info : virObjectRef:296 : 
OBJECT_REF: obj=0x7fb860000e30
2016-04-12 19:41:27.151+0000: 15224: info : virEventPollUpdateHandle:152 
: EVENT_POLL_UPDATE_HANDLE: watch=58 events=15
2016-04-12 19:41:27.151+0000: 15224: info : qemuMonitorSend:1005 : 
QEMU_MONITOR_SEND_MSG: mon=0x7fb860000e30 
msg={"execute":"query-status","id":"libvirt-7"}
  fd=-1

Looking at the dbus src, there's a 30s timeout defined here:

src/util/virdbus.c:# define VIR_DBUS_METHOD_CALL_TIMEOUT_MILLIS 30 * 1000

So, for some reason libvirt is trying to call a dbus method before every 
KVM instance start.  This leads to absurdly long startup times.  This 
behavior was not present in 1.3.1.

My workaround was to just recompile with '--with-firewalld=no 
--with-dbus=no', which seems to have worked.  There's not really 
anything useful for libvirt to be talking to via dbus (in our 
environment), so no big loss there.